#define   _CRT_SECURE_NO_WARNINGS 1
char* my_strstr(const char* str1, const char* str2)
{
	const char* s1 = (NULL);
	const char* s2 = (NULL);
	const char* cur = str1;
	if (*str2 == '\0')
		return (char*)str1;
	while (*cur)
	{
		s1 = cur;
		s2 = str2;
		while (*s1 == *s2 && *s1 != '\0' && *s2 != '\0')
		{
			s1++;
			s2++;
		}
		if (*s2 == '\0')
		{
			return cur;
		}
		cur++;
	}
	return (NULL);

}